Question 257898
(88+69+X)/3>=85
(157+X)/3>=85
157+X>=85*3
157+X>=255
X>=255-157
X>=98 THE GRADE NEEDED FOR AN AVERAGE OF 85 OR GREATER.
PROOF:
LET X=99
(88+69+99)/3>=85
256/3>=85
85.33>=85